This invention relates to a bag assembly for use in pharmaceutical manufacturing and for holding health care related solutions and, more particularly, to an apparatus and a method for use in the sterilization-in-place of such a bag assembly.
Bag assemblies including a flexible bag and tubing connections are currently used in many applications, including intravenous delivery, blood transfusion and pharmaceutical manufacture. Before being filled, the bag assemblies must be sterilized. This is conventionally done initially at the place of manufacture before the bag assemblies are shipped, and the sterile bag assemblies are placed within individual packaging which protects their sterility. When a bag assembly reaches the location where it is to be filled, and the outer package is opened, unless this is done in a sterile environment, the bag assembly loses its sterility. Usually, clamps are applied to the tubes so that the interior of the bag remains sterile, but the interiors of the tubes distally of the clamps lose their sterility. This interior then has to be resterilized before the bag can be filled. It would be desirable to provide an apparatus and a method whereby the bag assembly does not have to be initially sterilized at the place of manufacture but instead the bag and tube interiors can be sterilized in place immediately before the bag is filled and at the same station where the bag is filled.
At the present time, virtually all such bag assemblies are manufactured of polyvinyl chloride (PVC). PVC is a commonly used inexpensive plastic material which is naturally hard. To soften such material so that it can be used as a flexible bag and as flexible tubing, plasticizers such as phthalate esters are added to the PVC to soften it. Recently there has been concern that phthalates may leach from the PVC to which they have been added, thereby contaminating aqueous fluids held in PVC bags and traveling through PVC tubing. Since PVC bags are used to store intravenous solutions and blood for transfusions, phthalates which leach from the PVC are infused directly into a patient""s bloodstream. It has been proposed to provide a bag assembly manufactured entirely of silicone, which is phthalate-free and therefore obviates the above-discussed concerns. Such a bag assembly is formed of silicone tubing, with the bag being formed from large bore, thin walled silicone tubing and the inlet and outlet tubes being formed from small bore, thick walled silicone tubing. To sterilize such a bag assembly, it is known to use pressurized steam, which is an approved sterilization technique. However, the thin walled tubing making up the bag is limited insofar as the interior pressure it can tolerate. It would therefore be desirable to have apparatus which allows the interior of such a thin walled bag to be sterilized by pressurized steam while protecting the bag from excessive interior pressure which could rupture the bag.
According to the present invention, there is provided apparatus for use in performing sterilization-in-place of a silicone bag secured to a pair of tubes each communicating with the interior of the bag. The inventive apparatus comprises a plurality of rigid bag support members each including a respective cavity configured complemental to a respective portion of the exterior of the bag when the bag is inflated to a predetermined volume. The respective exterior portions together form the entire bag exterior with no overlap. The apparatus also includes at least one clamp coupled to the plurality of bag support members for holding together the plurality of bag support members so as to form a bag shell having an interior chamber equal in size and shape to the exterior of the bag when the bag is inflated to the predetermined volume.
In accordance with an aspect of the present invention, the apparatus further comprises a plurality of rigid tube support members each having a respective cavity configured complemental to a respective arcuate portion of the exterior circumference of a respective one of the tubes. The respective arcuate portions together form the entire respective tube exterior circumference with no overlap. At least one clamp is provided, which is adapted to hold together the plurality of tube support members so as to form a pair of tube shells each having an interior chamber equal in size and shape to a respective one of the tubes.
In accordance with another aspect of this invention, the plurality of bag support members consists of two rigid bag support members having substantially equal size cavities. The apparatus further comprises a hinge coupled to the two bag support members to allow pivoting movement about a pivot axis of one of the two bag support members relative to the other of the bag support members. The bag support member clamp has a first portion secured to one bag support member remote from the pivot axis and a second portion secured to the other bag support member remote from the pivot axis.
The inventive method for performing sterilization-in-place of a silicone bag secured to a pair of tubes each communicating with the interior of the bag comprises the steps of providing a plurality of rigid bag support members each including a respective cavity configured complemental to a respective portion of the exterior of the bag when the bag is inflated to a predetermined volume, wherein the respective exterior portions together form the entire bag exterior with no overlap, and placing the bag on at least one of the bag support members. Further steps include clamping the plurality of bag support members so as to form a bag shell having an interior chamber equal in size and shape to the exterior of the bag when the bag is inflated to the predetermined volume, and then applying pressurized steam to one of the tubes.